Since the launch of the first Earth observation satellite in 1959, the world has witnessed incredible developments in terms of platform and sensors to observe the Earth. It is now possible to see virtually any part of our planet and distinguish objects the size of a mountain up to the size of a coin.
One of the latest UAVs (unmanned aerial vehicles) is the Microdrone, developed by German Company microdrones GmbH. It has been used for a variety of monitoring and surveillance applications, as well as for aerial photogrammetry and infrastructure ...
An impressive bank of clouds hung over the Great Australian Bight in early fall, 2012, stretching thousands of kilometers from Perth, Western Australia to Adelaide, Southern Australia and beyond. The cloud bank also extended thousands of kilometers to the south, extending beyond the southern edge of this image and over the Indian Ocean. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Terra satellite captured this true-color image on March 23, 2012 at 1:45 UTC (12:45 p.m. local time). On that same day, Weatherzone reported that the first strong cold front of the season had surged up from the Southern Ocean, bringing the bitter gale wind to southeast Australia. Although that region is to the east of this image, the clouds seen in the Great Australian Bight are likely part of that same extensive cold front. The cloud formations seen in this image are both beautiful and complex. They appear to be primarily convective clouds, with an uneven cloud surface and readily recognizable independent cellular cloud areas. Convective clouds are formed when warm, humid air rises, such as over water that is warmer than the atmosphere. As air rises, it cools. When humid air is cooled sufficiently, water condenses onto tiny particles suspended in the air, forming droplets, and clouds are formed. A cold front is simply the leading edge of a cooler mass of air. As a large cold front moves over an expanse of warmer waters, conditions can become quite favorable for formation of a large bank of convective clouds.
Before the launch of a top-secret spy satellite from Vandenberg Air Force Base, a fleet of small drones will be doing some spying of their own. The Vandenberg crew will be using the drones to scan the launch safety zone before the liftoff, which has been delayed several times and now is scheduled to take place late onApril 3, 2012. The drones will be looking for intruders, including those who might be unaware of the pending launch or seeking a good vantage point from which to watch.......
While water levels of the Caspian Sea have historically fluctuated, the area has seen increasing water volume in the past two decades. The largest inland mass of water (with no outlet) is greatly influenced by the Volga River, which provides more than 80 percent of the lake’s volume. The Caspian, identified as either an inland sea or the largest lake in the world, is fed by over 120 rivers, but the Volga is the dominant source. Upstream precipitation in the greater Volga Basin contributes to the water levels of the Caspian. In the past decades heavy rains have greatly enlarged the flow into the Sea. The northern portion is characterized by relatively fresh water; because of evaporation, the southern portion has increased salinity.
These Landsat images show a portion of the Caspian Sea shoreline, in 1985 and again in 2011. Coastal settlements have been flooded, displacing inhabitants and closing industrial facilities. The level of groundwater also is rising, which leads to swamping and salinity of lowland territories. Tyuleniy Island (the prominent island) has visibly lost land mass, and the rising water contributes to the decline of the habitat of the island and the marshes around it that support fowl and other animals......
Segmentation of buildings in urban areas, especially dense urban areas, by using remotely sensed images is highly desirable. However, segmentation results obtained by using existing algorithms are unsatisfactory because of the unclear boundaries between buildings and the shadows cast by neighboring buildings. In this paper, an algorithm is proposed that successfully segments buildings from aerial photographs, including shadowed buildings in dense urban areas. To handle roofs having rough textures, digital numbers (DNs) are quantized into several quantum values. Quantization using several interval widths is applied during segmentation, and for each quantization, areas with homogeneous values are labeled in an image. Edges determined from the homogeneous areas obtained at each quantization are then merged, and frequently observed edges are extracted. By using a “rectangular index”, regions whose shapes are close to being rectangular are thus selected as buildings. Experimental results show that the proposed algorithm generates more practical segmentation results than an existing algorithm does. Therefore, the main factors in successful segmentation of shadowed roofs are (1) combination of different quantization results, (2) selection of buildings according to the rectangular index, and (3) edge completion by the inclusion of non-edge pixels that have a high probability of being edges. By utilizing these factors, the proposed algorithm optimizes the spatial filtering scale with respect to the size of building roofs in a locality. The proposed algorithm is considered to be useful for conducting building segmentation for various purposes
Saudi Arabia is drilling for a resource possibly more precious than oil by tapping hidden reserves of water in the Syrian Desert.
Over the last 24 years, it has tapped hidden reserves of water to grow wheat and other crops in the Syrian Desert. This time series of data shows images acquired by three different Landsat satellites operated by NASA and the U.S. Geological Survey.
An advanced French remote sensing satellite – SPOT-6 – weighing close to 800 kg will be launched by ISRO’s Polar Satellite Launch Vehicle (PSLV) from Sriharikota during the second half of 2012. Agreement signed
An agreement was signed recently between ISRO’s commercial wing Antrix Corporation Limited and Astrium SAS, a company under European Aeronautic Defence and Space Company (EADS), France, for the commercial launch of the satellite, said a press release from ISRO.
This nearly cloud-free view of Great Britain and Ireland was acquired by the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard NASA's Terra satellite on March 26, 2012. Just a few days into spring, most of the land appears green, although not quite as brilliant as the summertime hues that give Ireland the nickname's the Emerald Island. The islands of Ireland (west) and Great Britain (east) are separated by the Irish Sea, which is filled with the turquoise, green and tan swirls typical of sediment, although blooming algae could also contribute some color to the waters. To the southeast, the English Channel separates the island of Great Britain from France (south) and Belgium (north). London can be seen as a gray circle situated inland on the tan-colored River Thames. The sediment from the Thames flows into the English Channel due east of London. The United Kingdom is made up of Wales, Scotland and England, all located primarily on the island of Great Britain, and of Northern Ireland, which comprises the northern section of the island of Ireland. Dublin, in the Republic of Ireland, can be seen as a gray smudge on the eastern coast of the island. Almost due west Galway can be seen as a linear gray streak on the northern coast of Galway Bay, with the blue waters of Loch Corrib to the north. Most of the United Kingdom and Ireland are part of the Celtic broadleaf forest ecoregion, where acid-loving oak and mixed oak forests abound, along with fen and swamp forests and ombrotrophic mires. A portion of the Scottish Highlands, in the north of Great Britain, are covered by the Caledon conifer forest ecoregion. The Caledonia conifers once covered a large area of Scotland, but now only about 1% of the original forest survives, mostly high in the cooler areas of the Highlands.
In late March, 2012 sea ice hugged the shores of Russia's Sakhalin Island and covered much of the Sea of Okhotsk. As spring brings increasing sunlight to the region, the ice will begin to break up and flow out to the Pacific Ocean. On March 23, the Japanese Meteorological Agency predicted that ice would flow out of the Goyoumai Pass and the Kunashiri Pass near Hokkaido, Japan in the upcoming week, and warned ships to be cautious about the movement of sea ice. The National Snow and Ice Data Center (NSIDC) announced that the Arctic sea ice reached its maximum extent for the winter of 2011-2012 on March 18. The total extent was 15.24 million square kilometers (5.88 million square miles), which was below the 1979-2000 average, but still slightly above the record low, which was recorded during the winter of 2010-2011. The Sea of Okhotsk lies at a similar latitude as Portland, Oregon and Venice, Italy, and the Sea is the southernmost extent of Artic sea ice. It is generally icebound from November to June, and is frequently covered in heavy fog, making clear images, such as this one, difficult to acquire. The Moderate Resolution Imaging Spectroradiometer (MODIS) aboard the Aqua satellite captured this true-color image of the shifting sea ice on March 25, 2012.
rban agriculture is a phenomenon that can be observed world-wide, particularly in cities of devel-oping countries. It is contributing significantly to food security and food safety and has sustained livelihood of the urban and peri-urban low income dwellers in developing countries for many years. Population increase due to rural-urban migration and natural - formal as well as informal - urbani-sation are competing with urban farming for available space and scarce water resources. A mul-titemporal and multisensoral urban change analysis over the period of 25 years (1982-2007) was performed in order to measure and visualise the urban expansion along the Kizinga and Mzinga valley in the south of Dar Es Salaam. Airphotos and VHR satellite data were analysed by using a combination of a composition of anisotropic textural measures and spectral information...............
For more than 30 years, water has been diverted from the Amu-Darya and the Syr-Darya Rivers feeding the Aral, to irrigate millions of acres of land for cotton and rice production in Central Asia. This has caused a loss of more than 60% of the lake's water. The lake has shrunk from over 65,000 sq km to less than half that size, exposing large areas of the lake bed. From 1973 to 1987 the Aral dropped from fourth to sixth among the world's largest lakes.
The lake's salt concentration increased from 10% to more than 23%, contributing to the devastation of a once thriving fishery. The local climate has reportedly shifted, with hotter, drier summers and colder, longer winters.
As the water retreated, salty soil remained on the exposed lake bed. Dust storms have blown up to 75,000 tons of this exposed soil annually, dispersing its salt particles and pesticide residues. This air pollution has caused widespread nutritional and respiratory ailments, and crop yields have been diminished by the added salinity, even in some of the same fields irrigated with the diverted water.
Landsat satellite data, acquired and archived by the U. S. Geological Survey over the decades, are used by resource managers to measure the Aral Sea's extent and rate of drying. Each Landsat scene covers an area 170 km north/south x 185 km east/west (106 miles x 115 miles).
Satellite remote sensing involves gathering information about features on the Earth's surface from orbiting satellites. These satellites carry two types of sensor systems known as "active" and "passive". A "passive" system generally consists of an array of small sensors or detectors, which record (as digital numbers), the amount of electro-magnetic radiation reflected and/or emitted from the Earth's surface. A multispectral scanner is an example of a passive system. An "active" system propagates its own electro-magnetic radiation, and measures (as digital numbers), the intensity of the return signal. Synthetic Aperture Radar (SAR) is an example of an active system. The digital data acquired by the satellites is transmitted to ground stations and can be used to reconstitute an image of the Earth's surface not too dissimilar to an aerial photograph......
When an image is corrected for radiometric and geometric distortions, areas that are not of interest for the mapping purpose can be masked out. Such areas are: water, clouds, shadows.
This can be done by:
Using existing map or GIS files of the feature to be masked Using band ratios to extract the shaded areas Using NIR band to extract water as it does not penetrate water Delineating areas to be extracted